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BigLar368 · 09-14-2020, 11:51 AM

Quote:

Originally Posted by YC1

Just a side note on AC's in general. My grandson just changed his single Ac's unit out. The new one has a plastic frame and is incredibly unstable when not installed. That is beside the point.

I could not see any drains for the condenser so followed the troughs as best as I could and it seems they feed that condensate back to the "evaporator radiator"??? May have them switched, coffee is on the way to the brain right now. The fan picks it up and blows it over the radiator it seems.

The unit has two separate motors versus the one on my Dometics. The shrouding is much better designed that the ones I have but overall it is really a lightly built thing. The internals look fine but it took four of them to get one that was not damaged in shipping. He is an electrician and this new one seems quite a bit more efficient.

It is a make I have never heard of and can't remember.

Taking water made by the evaporator and pushing it onto the condenser coils sounds like a good idea. Water is just going to drain on the roof anyways. Seems like it would work.

geordi · 09-14-2020, 03:52 PM

Quote:

Originally Posted by BigLar368

Not even sure there are any relays that control or cycle the compressor. Either way it's parked under an RV cover. It also cycles the same at night without any heat near.

As far as the temp. sensor/probe it's a non-ducted AC so the temp probe is in the return air. I wrapped it up (the probe) with a couple of socks to insulate it incase that was the problem but it still did the same thing.

Reading through the installation manual, there is a warning that incorrect installation of the duct divider can cause short cycling. Since the AC seems to function perfectly when NOT using the ducting, that makes me wonder if there is a leak between the cold and return sides that is less obvious when the air can free-blow down. When that door you cut is closed, the pressure on the cold side is higher and might be forcing its way through to places it shouldn't be.

When I swapped out my most recent AC unit, I used aluminum tape to seal up the divider and ensure the cold air was going only where it was supposed to go.

geordi · 09-14-2020, 03:56 PM

Quote:

Originally Posted by BigLar368

Taking water made by the evaporator and pushing it onto the condenser coils sounds like a good idea. Water is just going to drain on the roof anyways. Seems like it would work.

This is not a new design idea - The Carrier AirV RV air conditioner units have had this feature for many years, they call it a "slinger wheel" but it doesn't really make a huge difference in the temperatures or the water runoff, especially in The South where an AC unit can produce many gallons of condensation water per day.

I've actually had to mod my Carrier units to drain easier b/c this water system will leak inside the coach b/c of how much it is producing. 85% outdoor humidity at 95 degrees will do that.

BigLar368 · 09-15-2020, 04:41 AM

Quote:

Originally Posted by geordi

Reading through the installation manual, there is a warning that incorrect installation of the duct divider can cause short cycling. Since the AC seems to function perfectly when NOT using the ducting, that makes me wonder if there is a leak between the cold and return sides that is less obvious when the air can free-blow down. When that door you cut is closed, the pressure on the cold side is higher and might be forcing its way through to places it shouldn't be.

When I swapped out my most recent AC unit, I used aluminum tape to seal up the divider and ensure the cold air was going only where it was supposed to go.

I did the same thing.....lol....That's what has me wondering if it's something else. I paid a lot of attention to that area of the installation. I did have to squeeze the power supply past the divider but I taped it up to keep air bleeding across from one side to the other. The instructions also specified that the divider be installed a specific direction and not upside down. I also confirmed that was installed correctly per the instructions. In the end I may pull the cover off the top just to make sure the thermocouple is where it's supposed to be. Right now as it sits it's only for supplemental cooling or if one unit craps out. Running it with the other two will only make the older ones work easier and cool better.

BigLar368 · 09-15-2020, 04:44 AM

Quote:

Originally Posted by geordi

This is not a new design idea - The Carrier AirV RV air conditioner units have had this feature for many years, they call it a "slinger wheel" but it doesn't really make a huge difference in the temperatures or the water runoff, especially in The South where an AC unit can produce many gallons of condensation water per day.

I've actually had to mod my Carrier units to drain easier b/c this water system will leak inside the coach b/c of how much it is producing. 85% outdoor humidity at 95 degrees will do that.

I actually thought this very same thing. I would be wiling to bet out house AC during the summer makes 25 gallons of water a day. We live on the coast so it's almost always humid here. I noticed the new AC the other day had a small stream of condensate running out of the unit. Not a fast drip but rather a constant stream...lol.

jacwjames · 09-15-2020, 05:53 AM

I'm building a new garage for my coach and made sure to put floor drains in the front and rear for the to capture it so it doesn't collect in the garage. Not sure how much I will be running the AC's while in the garage but I'm sure it was worth the effort.

BigLar368 · 09-15-2020, 08:28 AM

It's worth it just whenever you fell like washing down the floor if need be or washing the RV inside.....lol.

Diesel-Lover · 09-15-2020, 01:43 PM

Wondering if a three zone split cool might have been just the ticket for a quieter and more efficient set up? They have registers that mount on the wall at floor level or those chocolate bars at the ceiling. There is even a counter sunk option for the ceiling!

They have fantastic cooling with low noise and sophisticated control mechanisms, sensors and timers. Some can be set to detect people, vari during the sleep cycle to manage body cooling etc and the best function is managing the humidity. Since they use inverter technology efficiency is tremendous and the central compressor is variable speed.

BigLar368 · 09-15-2020, 03:03 PM

Quote:

Originally Posted by Diesel-Lover

Wondering if a three zone split cool might have been just the ticket for a quieter and more efficient set up? They have registers that mount on the wall at floor level or those chocolate bars at the ceiling. There is even a counter sunk option for the ceiling!

They have fantastic cooling with low noise and sophisticated control mechanisms, sensors and timers. Some can be set to detect people, vari during the sleep cycle to manage body cooling etc and the best function is managing the humidity. Since they use inverter technology efficiency is tremendous and the central compressor is variable speed.

Are you speaking of a mini split?

Diesel-Lover · 09-15-2020, 03:43 PM

Yes sir a minisplit or ductless heatpumps.

single unit with compressor and chocolate bar are very reasonable but for some reason as you add zones the price goes bonkers! But for an RV in the interest of weight etc I can kinda see the need for a multizone one. Perhaps a 2 zone could take care of the whole rig.

I put on two of these little munchkins on my house which already had central AC and heat as I found that those two rooms get occupied by folks, and they then influence the temps in the rest of the house as in freezing in the summer and too hot in the winter!

Here is one I randomly pulled from Lowes.
https://www.lowes.com/pd/MRCOOL-Olym...TAR/1002647132

geordi · 09-15-2020, 04:33 PM

Quote:

Originally Posted by Diesel-Lover

Yes sir a minisplit or ductless heatpumps.

single unit with compressor and chocolate bar are very reasonable but for some reason as you add zones the price goes bonkers! But for an RV in the interest of weight etc I can kinda see the need for a multizone one. Perhaps a 2 zone could take care of the whole rig.

I put on two of these little munchkins on my house which already had central AC and heat as I found that those two rooms get occupied by folks, and they then influence the temps in the rest of the house as in freezing in the summer and too hot in the winter!

Here is one I randomly pulled from Lowes.
https://www.lowes.com/pd/MRCOOL-Olym...TAR/1002647132

I've been thinking about these units for a while, you aren't the first to think about them either. There are some issues with them however. The interior wall units aren't small, and in an RV that can be a problem for finding a place to put it! They don't have a design (that I've seen yet) that would work with the roof opening that the RVs already have - although since the compressor and condenser can be mounted elsewhere, this isn't as much of an issue that the existing airbox COULD be modified. I've already decided that if I have a failure of one of my Carrier units, that I might take on the project of adapting the minisplit to use my Carrier roof evaporator. I think it's certainly possible.

The last issue is the main one - MOST of the units I've seen that are rated over 12k BTU are requiring 220 volt power, which in the RV is a bit difficult. Apparently (not sure of other coaches) the Onan QD7500 I have is not actually producing 220VAC, but 2 lines of 120VAC that are precisely on the same phase. When you meter across the hot legs, there is zero voltage showing.

Diesel-Lover · 09-15-2020, 05:01 PM

The last issue is the main one - MOST of the units I've seen that are rated over 12k BTU are requiring 220 volt power, which in the RV is a bit difficult. Apparently (not sure of other coaches) the Onan QD7500 I have is not actually producing 220VAC, but 2 lines of 120VAC that are precisely on the same phase. When you meter across the hot legs, there is zero voltage showing.

Perhaps this will solve your 220V issue. The ceiling insert option should fit well into the opening though one would have to enclose it from the top!

https://www.amazon.com/Air-Ductless-.../dp/B01F5Z3JDE

I have seen an ingenious fellow take a window AC apart and fit it under a sofa with the compressor and heat exchanger below in the frame rails. The evaporator was right above so the condensate helped with cooling the heat exchanger!

Needless to say I love the minisplit systems they are the cats meow.

BigLar368 · 09-15-2020, 05:19 PM

Quote:

Originally Posted by Diesel-Lover

Yes sir a minisplit or ductless heatpumps.

single unit with compressor and chocolate bar are very reasonable but for some reason as you add zones the price goes bonkers! But for an RV in the interest of weight etc I can kinda see the need for a multizone one. Perhaps a 2 zone could take care of the whole rig.

I put on two of these little munchkins on my house which already had central AC and heat as I found that those two rooms get occupied by folks, and they then influence the temps in the rest of the house as in freezing in the summer and too hot in the winter!

Here is one I randomly pulled from Lowes.
https://www.lowes.com/pd/MRCOOL-Olym...TAR/1002647132

I am familiar with them however I do not think it would be practical for a motorhome. I can't imagine where the condenser unit would be placed as well as running the copper lines through the ceiling.

geordi · 09-15-2020, 05:44 PM

Quote:

Originally Posted by BigLar368

I am familiar with them however I do not think it would be practical for a motorhome. I can't imagine where the condenser unit would be placed as well as running the copper lines through the ceiling.

That's just my point - you don't run through the ceiling. The existing RV outdoor upper unit has both evaporator and condensers, connected by the tubing. The mini-split box can sit on the roof behind where the "RV" unit sits, and only the existing evaporator coil with the existing fan and plenum box that cycles the air would sit over the roof hole... As it does right now. Everything stays outside.